Sleep habits influenced by genetics and behavior, expert says

Sleep habits influenced by genetics and behavior, expert says
Dr. Emerson Wickwire, director of the insomnia program at the University of Maryland School of Medicine, treats patients at the University of Maryland Sleep Disorders Center. (Photo courtesy of University of Maryland)

It's not uncommon to hear people say they feel tired, whether it's because of a new work schedule, a new baby or just a hectic lifestyle. The answer for most is just getting enough sleep at a consistent time, said Dr. Emerson Wickwire, an assistant professor and director of the Insomnia Program at the University of Maryland School of Medicine who treats patients at the University of Maryland Sleep Disorders Center. But sometimes new strategies are needed, said Emerson, also president of the Maryland Sleep Society.

How much sleep do people really need, and what makes a schedule normal?


It's one of the most common questions that I'm asked. The average adult needs between seven and nine hours of sleep per night. Even so, in my experience, the vast majority of Americans are chronically sleep-deprived. Partner with your family to run a two-week behavioral experiment: nine hours of sleep per night, every night. See how much better you look and feel. Then decide.

What makes someone a night owl or a morning person?

Sleep scientists refer to these distinctions as chronotypes. Roughly half of middle-age adults are intermediate types, with the remainder being evenly split between morning types and evening types. There is strong scientific evidence that eveningness is associated with increased risk of multiple health problems and other negative consequences.

Our chronotype is largely influenced by genetics (about 50 percent), with the remainder influenced by the environment and our behavior. Light is the strongest of these external regulators, because it suppresses melatonin, a well-known hormone that tells our body when it's dark outside. Other behavioral factors include the time we eat our meals, when we choose to exercise, and even how we schedule our social activity. So our circadian predisposition can't be completely reversed, but it can be modified by our behavioral choices.

What happens when someone suddenly has to change his sleep pattern because of a job or a baby?

From time to time, we're all faced with stressful life situations. Some of these, like having a newborn, will pass. Others, like taking a position on the night shift, will require more sustained lifestyle change. So really, these situations require fundamentally different approaches. The most important thing is to make sure that you're obtaining adequate sleep — seven to nine hours per night — at a consistent schedule as possible.

Is taking melatonin safe in the short term and the long term? What are other therapies?

Melatonin is a sleep-related hormone that tells our brain that it's dark outside. Early in the night, this is related to sleep onset, and in the morning, melatonin levels decrease as our sleep period ends. The fact is, though, that melatonin does not make us sleep. So even though melatonin is sold everywhere from the pharmacy to the gas station, if you're having general trouble sleeping, melatonin is almost certainly not your answer. In terms of safety, in the U.S., melatonin is not regulated by the Food and Drug Administration, so you're never 100 percent certain what you're actually buying. That aside, the most common side effects are next-day grogginess (particularly at high doses), headache and mood disturbance. Melatonin can also cause nightmares or vivid dreams. But it's generally considered safe, and people take it all the time. I recommend a pharmaceutical-grade melatonin, but patients are often surprised by our recommendations for timing and dose.

When we treat circadian rhythm disorders — for example, shift work disorder and delayed sleep phase syndrome (staying up too late and having a hard time waking up), two common problems of circadian misalignment — we employ strategies that leverage light, behavior and frequently melatonin to help reset the body's clock and ensure adherence to the new schedule. We sometimes use medication, but we always employ a patient-centered approach.

When is it clear a person can't adjust, and what problems can lack of sleep cause?

Insufficient and disturbed sleep can cause or exacerbate problems ranging from depression to dementia, obesity to diabetes, and stroke to heart attack, not to mention dramatically increased risk for serious accidents like a motor vehicle crash. When it comes to your health, there is virtually no bodily function that cannot be impaired by poor sleep.